The photoreactions between 1,4-quinones (1 and 4) and aldehydes (2 and 5), yielding acylated hydroquinones as sole products, were investigated under artificial and solar irradiation conditions. Three different solar reactors were used for the photochemical syntheses with sunlight (PROPHIS, CPC and a flat bed reactor), and the CPC system was found to be the most robust one in terms of weather dependence. The solar reactions can be easily performed on a half-kilogram scale using cheap and commercially available starting materials.